Filtration
Filtration in winemaking is used to accomplish two objectives, clarification and microbial stabilization. In clarification, large particles that affect the visual appearance of the wine are removed. In microbial stabilization, organisms that affect the stability of the wine are removed therefore reducing the likelihood of re-fermentation or spoilage.
The process of clarification is concerned with the removal of particles; those larger than 5–10 micrometers for coarse polishing, particles larger than 1–4 micrometers for clarifying or polishing. Microbial stabilization requires a filtration of at least 0.65 micrometers. However, filtration at this level may lighten a wine's color and body. Microbial stabilization does not imply sterility. It simply means that a significant amount of yeast and bacteria have been removed.
Clarification of the wine can take place naturally by putting the wine into refrigeration at 35°F (2°C). The wine takes a month to settle and it is clear. No chemicals are needed.
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